Depth under keel bug
 

Is there any way to avoid this problem of the depth under keel function that stops working after a TC run?

It sometimes stops working for me but it doesn't seem to have anything to do with TC. When it doesn't work, it doesn't work from the moment I start the game. When it is working, it never stops working during the same session.

But to answer your question, I am unaware of a fix. I'm pretty sure there isn't one.

I'm having the same problem. It would work fine for part of the patrol then all of a sudden it would quit working. I'm on my first patrol and this has happened two or three times. I restarted the patrol each time it happened. It finally worked fine yesterday until I got myself killed. I'm now starting the same patrol all over again. Been going all day without the depth under keel problem. I can't explain why it goes bad or why it's good. For now anyway.